1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to a digital audio amplifier system, and more particularly, to a method and apparatus for controlling a power supply of an audio amplifier by changing the power supply voltage supplied to a power switching circuit unit of the audio amplifier.
2. Description of the Related Art
In general, digital audio systems use audio amplifiers, which are classified into class-A, class-B, class-AB, and class-D audio amplifiers. Class-D audio amplifiers may prevent amplification efficiency reduction caused in class-A, class-B, and class-AB audio amplifiers.
Class-D audio amplifiers are classified as open loop type or closed-loop type, and change an audio signal into a pulse width modulation (PWM) signal.
A class-D audio amplifier generally drives a power switching circuit by using a high fixed power value corresponding to a maximum audio output. The class-D audio amplifier that operates at high power may cause device heating or generate noise in neighboring electronic devices.
Accordingly, a technology for appropriately controlling power supply voltage of an audio amplifier is needed.